Adjusting means for chain wrench



Dec. 11, 1951 K. SELFRIDGE ADJUSTING MEANS FOR CHAIN WRENCH Filed May 19, 1947 //\/ME/\/ TUF? LEROY K SE-LFRIDGE:

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/ T 7 NEVE Patented Dec. 11, 1951 UNITED STATES PATENT OFFICE ADJUSTING MEANS FOR CHAIN WRENCH Leroy K. Selfridge, Portland, Oreg.

Application May 19, 1947, Serial No. 748,917

This invention relates to an improved wrench having a flexible gripping element adapted to bind and grip round objects such as pipe and also angular objects such as nuts and bolt heads.

Objects "of the present invention are to provide a wrench having a flexible gripping element which is particularly adaptable to use in confined places and to objects such as pipesor bolt heads lying closely adjacent a wall surface or other obstruction which would prevent the effective manipulation of a conventional wrench, to provide a wrench having a chain grip to engage objects of any shape, to provide a wrench with-an encircling gripping element having a ratchet type action to tighten or loosen objects where there is limited freedom for handle movement, and to provide an exceptionally sturdy though economical construction capable of exerting an unusually powerful grip on smooth cylindrical objects which are difficult to grip with conventional wrenches.

The gripping element of the present wrench comprises a flexible member, preferably'in the form of a link chain for heavy work, which, by a novel arrangement and pivotal mounting of the parts, is adapted to exert an extremely powerful gripping action upon an object to be turned or twisted. The gripping action of the flexible member is such that the grip may be tightened in any angular position of the wrench and the object may be turned effectively with a very small amount of handle movement. The construction permits a slight amount of reverse movement of the handle to loosen the chain grip to readily slip back and obtain a new hold on the object with a relatively small amount of lost motion inthe loosening and tightening movements. This desirable mode of operation is accomplished by removably securing one portion or end of the chain grip in an anchor member pivotally mounted on a handle. A bight is formed in the chain on one side of the anchor member to encircle and grip the object to be turned, and another portion or endof the chain is adjustably anchored in'the handle. Between the handle and the workengaging bight the chainis trained around a fulcrum guide surface at a distance from the pivotal mounting of the handle so that relative movement of the handle in one direction with respect to the anchor member shortens and tightens the chain in the bight. When the chain has been pulled tight in this manner the force applied to the handle thereby continues to hold the chaintight 1 .the object with a powerful force related-to the turning effort Which must be exerted to turn the object. When the handleis movedin-the oppo- 2 Claims. (01. 81--66).

site direction the chain is loosened sufliciently to slip on the object with a ratchet-like action.

These and other objects and advantages will become apparent from the following description in connection with the accompanying drawings illustrating a preferred embodiment of the invention.

In the drawings: Figure 1 is a view of the wrench applied to a p p Figure 2 is a cross sectional view taken on the line 2-2 of Figure 1;

Figure 3 is a fragmentary perspective view the handle; and

Figure 4 is a sectional view taken on the line 4-4 of Figure 1 showing the locking means for adjustably anchoring one end of the flexible gripping element. i

The various operative parts of the wrench are carried by or mounted on a hollow handle I 0. A chain anchor comprising a slider II is mounted to slide longitudinally within the hollow handle and is adapted to lock in different positions to adjust the useful length of the chain which'is allowed to extend from the handle. One side of the handle is provided with a longitudinal slot 12' through which a thumb or finger piece I3 projects, the opposite sides of the slot having recesses 14 to engage detents l5 on the slider to hold it in diiierent selected positions. A spring l6, carried by the slider, normally urges the detents into these recesses, but by pressing the thumb or finger piece I 3 into the handle the detent may be disengaged from the recesses to move the slider to any desired position.

A pin l1 secures one end of the gripping chain [8 to the slider, allowing the other end of the chain to extend out of the end of the handle. The handle has a bracket arm l9 alongside the chain and provided with a pivot pin 20 for pivot- I ally mounting a gripping anchor member 2|. The member 2| has an opening 22 through which the chain passes and a notch or hook 23 for removably engaging and anchoring a pin 24 on the free end of the chain.

Thus, when thepin 24 is engaged in the notch 23, a portion of the chain near the free end may be looped into a bight 25 to encircle and grip an object to be turned. Because of the articulating pin connected joints between the chain links, the chain is adaptedto accommodate itself approxi mately to the surface contour of any angular or curved surface. The chain links'are provided with hardened teeth 28 to bite into smooth surfacedobjectssuch aspipes to prevent slippage of the chain. When a pipe 30 or other object is gripped by the chain it is pulled into engagement with other teeth 3| formed on the gripping member 21 to assist the teeth 26 in preventing slippage. Preferably, all these teeth are inclined in the manner shown to bite in one direction of twist and slip in the reverse direction to facilitate a ratchet-like action, as will presently be described. The numeral 32 de ignates a wall portion or bridging member interconnecting opposite side walls of the member 2! on the opposite sides of the opening 22 to provide stiffness and rigidity in this member and to serve as a chain guide defining another wall of the opening 22.

When the handle I is swung about the pivot 20 in the direction of the arrow 35, it is apparent that the chain in the bight 25 will be slackened so that the chain and wrench as a whole will be free to slide around the pipe in a counterclockwise direction. The previously mentioned inclination of the teeth 26 and 3| permits sliding in this direction. By reason of the fact that the chain is trained over an arcuate guide surface 36 forming a wall of the opening 22 at a distance from the pivot pin 20, any movement of the handle in a clockwise direction, as indicated by the arrow 31, causes a certain length of chain to be pulled through the opening '22 to con-,

tract or tighten the bight 25. The arcuate surface 36 thereby acts as a fulcrum or drum upon which a powerful leverage is exerted by the handle to wind up a portion of the chain as the handle rotates with respect to the member 2|. After the chain is pulled tight on the pipe 30, so that the handle can no longer rotate with respect to the member 21 to pull through more chain, the wrench must rotate as a whole to twist the pipe. In this way the turning effort exerted onthe pipe by force applied to the wrench handle also exerts a contractive gripping force upon the chain in proportion to the turning force exerted upon the pipe. With this direction of twist the teeth 26 and 3! bite into the pipe and do not permit slippage. Since the handle H! has a wide range of angular movement on the member 2!, there is no practical limit imposed upon the contraction of the chain bight if strong resistance is encountered in attempting to turn the object. In most conventional pipe wrenchesthe amount of clamping or biting action is positively limited by design, so that no amount of force on the wrench handle is effective to increase the clamping action beyond a certain point. Ona pipe that is hard toturn, most conventional wrenches, therefore, tend to take a shallow bite and then slip on the pipe, scraping off a skin of metal and automatically losing their grip. It is impossible for the present wrench to lose its grip in this manner. It will also be apparent that the present wrench may be used on pipes very close'to a wall surface, or even lying against such a surface if any part of the pipe can be pulled out sufllciently to pass the free end of the gripping chain between the pipe and the wall. The slider ll may then hespulled up and. anchored at. apoint. to; place the handle in the most advantageous position (or doing the work required. Only a very small handle movement is required to operate the wrench because the inherent ratchet-like action enables the gripping chain to be tightened. on the object in any position of the handle so the full available handle stroke may. be. used. to tan: the object. The gripping elementneed not necessarily boa 4 link chain of the particular type shown. For certain purposes a metal or leather band or strap may be substituted for the chain. A leather strap would be advantageous, for instance, for use on more fragile objects such as screw caps on bottles and jars, and for objects having polished surfaces such as nickel or chromium plated pipes where the usual biting teeth would be objectionable. Such a strap is capable of exerting a powerful torque without flattening or crushing the object' to which it is applied.

Various other changes may be made in the construction, arrangement and proportion of parts, and all such modifications within the scope of the appended claims are included in the invention.

Having now described my invention in what manner the same may be used, what I claim as new and desire to protect by Letters Patent is:

1. A pipe wrench comprising a hollow tubular handle having a longitudinal slot on one side of the handle, a sliding anchor in said handle. a thumb piece on one side of said anchor pro jecting out through said slot to move said anchor, detents on said one side of said anchor, a spring on the opposite side of said anchor having sliding engagement with the interior of said handle, a series of detent engaging means inv said handle spaced along said slot to secure said anchor in diiferent adjusted positions, a gripping chain having one end attached to said sliding anchor within said handle, a pivot on one end of said handle at said one side of the handle, a pivotal anchor member having one end mounted on said pivot and having a free end extending across said end of the handle,

means on said free end of said pivotal anchor member for detachably securing the other end of said gripping chain; and a curved guide surface for the chain forming one wall of an opening in said end of the handle and extending partially'around said pivot at a distance from the pivot axis to form a fulcrum for tightening'said gripping chain around an object upon relative pivotal movement of said handle and pivotal anchor member, the opposite side of said handle having a smooth, uninterrupted exterior surface extending the full length of the handle for grasping the handle to apply said relative pivotal movement.

2. A pipe wrench comprising a hollow tubular handle-having open ends and a longitudinal slot on one side of the handle extending from one end of .the handle and terminating at. a point near the other end of the handle, aslidingan chor in the handle havinga thumbpiece project ing out through said slot to move said anchor, detents onsaid sliding anchor adjacent said thumb piece, detent engaging means in said handle spaced along said slot, a spring member on said sliding anchor having sliding engagement with the interior of said handle to urge said detentstoward said detent engaging means to lock. said anchor in selected positions, a pipe gripping chain having one free end and amend attached to said sliding anchor within the hendle, said chain and sliding anchor being insert able into said one end of the handle, a pivot on the other end of. thehandle atsaid one side. of the handle, a pivotal anchor member having one end mounted on said pivot and having'a free end across said other end. 01'- the handle, notches in said: free end of said pivotal anachormember for detachable. engcgen'ientwith end of said'grippms=chahi;'md and 5 a: crum for tensioning said chain having a guide surface for the chain extending around one side of said pivot and into said other end of the handle toward the terminus of said tslot, the opposite side of the handle having a smooth, uninterrupted grasping surface extending the full length of the handle.

LEROY K. SELFRIDGE.

REFERENCES CITED The following references are of record in the file of this patent:

Number Number 6 UNITED STATES PATENTS Name Date Evans Mar. 7, 1876 Chipchase et a1 Nov. 28, 1911 Bates May 19, 1914 Petrok Dec. 13, 1921 Wallace Jan. 15, 1924 Claybrook Sept. 3, 1929 Donoran Oct. 4, 1938 Dodson Dec. 20, 1938 Donovan Apr. 20, 1943 FOREIGN PATENTS Country Date Australia Mar. 29, 1934 

